* Australian IPO market is down 59 pct in H1 2015
* Listing would rank among Australia's top 5 of the year
* Signals return to health sector listings (Recasts with IPO market context, timing of sale)
By Byron Kaye
SYDNEY, Aug 25 (Reuters) - I-MED Radiology Network, Australia's biggest medical imaging firm, plans to raise A$500 million ($360 million) in an initial public offering, a source with knowledge of the matter said - a rare sign of life in an extremely weak year for Australian listings.
The planned IPO would likely rank among Australia's top five this year. Concerns about China's economic slowdown, a U.S. interest rate hike and Europe's exposure to Greek debt have hit appetite for new listings.
Sydney-based I-MED has hired Goldman Sachs (NYSE:GS) GS.N and Macquarie Group Ltd MQG.AX to help sell about half of its shares, which would give it a market capitalisation of around A$1 billion, said the source.
The company and its bankers plan to conduct the listing before the end of 2015, the source added, declining to be identified as he was not authorised to speak about the matter to media.
Representatives for I-MED, Goldman and Macquarie were not immediately available for comment.
Some A$2.4 billion of announced Australian IPOs have been cancelled and the value of IPOs for the first half of the year has plunged 59 percent, according to Thomson Reuters data.
The share sale plans, however, underscore the relative strength of Australian health companies after the sector was responsible for more than half of all IPOs in 2014 - a record year for listings.
The company that was responsible for the biggest listing of last year, health insurer Medibank Private Ltd MPL.AX , is trading 14 percent above its issue price following its November debut. The No. 2 listing, hospital company Healthscope Ltd HSO.AX , is trading 21 percent over its issue price.
I-MED has some 200 clinics and conducts 4 million patient procedures a year, according to its website.
($1 = 1.3847 Australian dollars)